Cross-linked nitrogen- and chlorine-containing cellular plastics and a method for the preparation thereof

ABSTRACT

Cross-linked cellular plastics having either open or closed cell structures are prepared from chloronitrosylated hydrocarbon polymers, having a chlorine content of from 0.5 to 73 percent by weight and a nitrogen content of from 0.01 to 5 percent by weight. The resulting cellular plastics possess improved physical properties.

United States Patent Inventors: Herwart C. Vogt, Grosse Ile; Pauls Davis, Gibraltar, both of Mich.

Assignee: BASF Wyandotte Corporation, Wy-

dotte, Mich.

Filed: Feb. 26, 1971 Appl. N0.: 1 19,386

Field of Search ..260/2.5 R, 2.5 HA, 96 HA,

1451 si ks-19, 912.

[s41 CROSS-LINKED NITROGEN- AND [56] References Cited CHLORINE-CONTAINING CELLULAR PLASTICS AND A METHOD FOR THE- UNITED STATES PATENTS PREPARATION THEREOF 3,498,934 3/1970 Kraemer et a]. 260/2.5 HA

Primary Examiner-Murray Tillman Assistant Examiner-wilbert J. Briggs, Sr. Attorney.loseph D. Michaels, Bernhard R. Swick, Robert M. Phipps and Robert E. Demn [57] ABSTRACT Cross-linked cellular plastics having either open or closed cell structures are prepared from chloronitrosylated hydrocarbon polymers, having a chlorine content of from 0.5 to 73 percent by weight and a nitrogen content of from 0.01 to 5 percent by weight. The resulting cellular plastics possess improved physical properties.

18 Claims, N0 Drawings CROSS-LINKED NITROGEN- AND CHLORINE- CONTAINING CELLULAR PLASTICS AND A METHOD FOR THE PREPARATION THEREOF The present invention relates to cellular plastics, i.e., foams having either open or closed cell structures prepared from hydrocarbon polymers containing both chlorine and nitrogen atoms. More particularly, the invention relates to the preparation of cross-linked cellular plastics from a blowing agent and a hydrocarbon polymer containing polar groups.

It is known to use chlorine-containing polymers in the preparation of expanded materials by incorporating in the polymer a chemical'blowing agent which, under the influence of heat evolves gas, whereby cells are formed and a low density product is produced. However, the prior art processes suffer several disadvantages. One major disadvantage of the prior art foams prepared from chlorine-containing hydrocarbon polymers is that the foams remain thermoplastic and, therefore, thoroughly soluble in common solvents such as benzene and carbon tetrachloride.

Now, in accordance with the subject invention, it has unexpectedly been found that infusible, insoluble, ther moset foams based on chlorineand nitrogen-containing hydrocarbon polymers may be prepared in a onestep process by heating a chlorineand nitrogen-containing polymer with a blowing agent at a temperature sufficient to release the gas from said blowing agent and to effect the cross-linking of the polymer. Generally, the process of the subject invention is carried out at temperatures of from 50 to 250 C., preferably from 75 to 190 C.

Any of the well-known chemical and solvent blowing agents can be used in the preparation of the foams in accordance with the subject invention. Illustrative chemical blowing agents include azobis(formamide), azodicarbonamide, diazoaminobenzene, N,N'- dinitrosopentamethylene tetramine, N,N-dimethyl- N,N'-dinitrosoterephthalamide, p,p'-oxybis(benzenesulfonyl semi-carbazide), azobis(isobutyronitrile), p,p-oxybis(benzenesulfonyl hydrazide), p,p'-diphenyl-bis(sulfonyl hydrazide), benzenesulfonyl hydrazide, m-benzene-bis(sulfonyl hydrazide). Illustrative solvent blowing agents include fluorocarbons such as tetrafluoromethane, bromotrifluoromethane, chlorotrifluoromethane, dibromodifluoromethane, dichlorodifluoromethane, trichlorofluoro-methane, hexafluoroethane, 1,2,2-trichloro-l ,1 ,2- trifluoroethane, 1 l ,2,2-tetrachloro-1 ,2-

difluoroethane, l ,2-dibromo-l ,1 ,2,2-tetrafluoroethane,

cyclopropane, octafluorocyclo-butane-l ,l ,2-dichloro- 1,2,3 ,3,4,4-hexafluorocyclobutane, 1,2,3 ,4- tetrachloro-l ,2,3 ,4-tetrafluorocyclobutane, trichloroethylene, chloroform, carbon tetrachloride, and low boiling hydrocarbons, such as butane, pentane, hexane, and toluene. Inorganic blowing agents, such as metal halides, alkaline and alkali earth carbonates, bicarbonates, ammonium carbonates and bicarbonates may also be employed in the subject invention as well as various forms of ammonium nitrite. Accordingly, any compound which decomposes or volatilizes to yield at least one mole of gas per mole of blowing agent at a temperature of 250 C. or less can be used.

The hydrocarbon polymers containing chlorine and nitrogen atoms which are employed in the subject invention are prepared by the reaction of a hydrocarbon polymer with nitrosyl chloride or chlorine and nitric oxide, generally in the presence of a catalyst. The chloronitrosylated polymers have a chlorine content of from 0.05 to 73 percent by weight and a nitrogen con-,

hydrocarbon polymers include polyolefins such as polyethylene, polypropylene, polybutylene, the higher 1,2,2-tribromo-l ,l,2-trifluor0ethane, octafluoropropane, decafluorobutane, hexafluorocyclopropane, 1,2,3-trichloro-l ,2,3-trifluoropolyalkylenes, copolymers prepared from mixtures of olefins such as polyfethylene-propylene), chlorinated polyolefins such as chlorinated polyethylene, polystyrene, poly(methylstyrene), poly(a-methylstyrene), polybutadiene, polyisobutylene, chloroprene, butyl rubber, poly(styrene-butadiene), polysulfone, polyvinylidenechloride, polyvinylidenefluoride, vinyl halide polymers, homopolymers or copolymers, polyvinyl-chloride, vinylchloride-vinyl acetate copolymers, vinyl chloride-vinyl acetal copolymers, vinyl chloridevinylidene chloride copolymers, vinyl chlorideacrylonitrile copolymers, vinyl chloride-1,2-ethylene dicarboxylic acid alkyl ester copolymers, such as vinyl chloride-diethyl fumarate copolymers, vinyl chloridediethyl maleate copolymers; vinyl chloride-vinylidene chloride-acrylonitrile terpolymers, vinyl chloride-vinyl acetate-maleic anhydride 'terpolymers, etc. Either plastisol or plastic grade vinyl chloride polymers can be used since this invention is equally applicable to either type. In addition to the above, blends of vinyl chloride polymers with certain other polymers can be used. Ex emplary polymers which can be blended with a vinyl chloride polymer are polychloroprene, butadieneacrylonitrile copolymers, butadiene-methyl isopropenyl ketone copolymers, butadiene-vinyl pyridine copolymers, butadiene-ethyl acrylate copolymers, polyisobutylene, polyethylene, styrene-butadiene copolymers, and natural rubber. Various types of foams can be prepared from the vinyl chloride polymers described above, depending upon the specific polymer used. For example, poly(vinyl chloride) yields rigid and semi-rigid foams whereas flexible foams are obtained from poly(vinyl chloride) plastisols and the vinyl chloride copolymers.

In a preferred embodiment of the subject invention, the chloronitrosylated hydrocarbon polymer is blended with conventional compounding agents before the blowing agent is added thereto. Compounding agents such as accelerators or activators, catalysts, fillers, stabilizers, antioxidants, antiozonants, plasticizers and positive chlorine compounds may be used. Representative accelerators or activators include metal salts such as dibasic lead phosphite, tribasic lead maleate and tribasic lead sulfate; and long-chain (C -C fatty acids such as lauric acid, palrnitic acid, oleic acid and stearic acid. Mixtures of the above may also be employed. Generally, the accelerators or activators are employed in conventional amounts, e.g., from 1 to 20 parts, preferably from 5 to parts, based on 100 parts by weight of polymer. Representative catalysts include free-radical initiators such as hydrogen peroxide, tbutyl peroxide, di-t-butyl peroxide, benzoyl peroxide, tertiary butyl hydroperoxide and dicurnyl peroxide, and azo compounds such as azobis(isobutyronitrile). Other peroxide initiators which may be employed in the present invention include cumene hydroperoxide, dichlorobenzoyl peroxide, tertiary butyl perbenzoate, acetyl benzoyl peroxide, caprylyl peroxide, lauryl peroxide, hydroxyheptyl peroxide, methyl ethyl ketone peroxide, l-hydroxycyclohexyl hydroperoxide-l ditertiary butyl perphthalate, dibenzaldiperoxide, 2,2-(tertibis(chloroacetyl)-peroxide. Reference is made to a book entitled Radical Polymerization by J. C. Bevington, (Academic Press, 1961), pages 5-28, for a detailed discussion of well-known, free-radical initiators which may be employed. Generally, from 0.1 part to 10 parts, preferably from 1 to 5 parts by weight of free-radical catalyst per 100 parts by weight of polymer will be employed.

The cross-linking reaction may also be carried out in the presence of a filler. Both reinforcing and non-reinforcing fillers may be used. Representative of such fillers are carbon black, titanium dioxide, precipitated silica, calcium carbonate, clay, and talc. In addition to the above-mentioned compounding agents, any other conventional compounding agents may be employed. These agents may be employed in conventional, non-critical amounts, e.g., from 3 to 50 parts by weight or more per 100 parts by weight of the polymer. Illustrative agents include stabilizers, antioxidants, antiozonants, plasticizers and positive chlorine compounds. Representative stabilizers include organo tin compounds, barium cadmium phosphite, epoxidized soybean oil, dibasic lead phthalate, dibasic lead stearate and dibasic lead succinate. Representative antioxidants and antiozonants include hindered phenols, such as 2,6-di-tert-butyl-para-cresol; heterocyclics, such as the phenothiazines; large variety of amines, such as N,N'-di-fi-naphthly-p-phenylene diamine; esters, such as n-octadecyl fl-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; sulfur containing compounds, such as 4,4'-thiobis(3-methyl-6-t-butyl phenol). In addition, such classes as mercaptans, sulfides, disulfides, mercaptals, dithiocarbamates, dithiophosphates, trithiophosphites and phosphite esters of alkyl, aryl, and mixed types may be used. Representative plasticizers include chlorinated diphenyl, dioctyl phthalate, dioctyl sebacate, dioctyl adipate, tricresyl phosphate and epoxy higher esters having from 22 to 150 carbon atoms. Such esters will initially have had unsaturation in the alcohol or acid portion of the molecule, which is taken up by the formation of the epoxy group.

Typical unsaturated acids are acrylic, oleic, linoleic, linolenic,erucic, ricinoleic and brassidic acids, and these may be esterifiedwith organic monohydric or polyhydric alcohols, the total numberof carbon atoms of the acid and the alcohol being within the range stated. Typical monohydric alcohols include but'yl'alcohol, 2-ethyl hexyl alcohol, lauryl alcohol, isooctyl alcohol, stearyl alcohol, and oleyl alcohol. The octyl alcohols are preferred. Typical polyhydric alcohols include pentaerythritol, glycerol, ethylene glycol, 1,2- propylene glycol, 1,4-butylene glycol, neopentyl glycol, ricinoleyl alcohol, erythritol, mannitol and sorbitol. Glycerine is preferred. These alcohols may be fully or partially esterified with the epoxidized acid. Also useful are the epoxidized mixtures of higher fatty acid esters found in naturallyoccurring oils such as epoxidized soybean oil, epoxidized olive oil, epoxidized tall oil fatty acid esters, epoxidized coconut oil and epoxidized tallow. Of these, epoxidized soybean oil is preferred.

The alcohol can contain the epoxy groupand have a long or short chain, and the acid can have a short or long chain, such, as epoxystearyl acetate, epoxystearyl stearate, glycidyl stearate, and polymerized glycidyl methacrylate.

As discussed above, in preparing foams in accordance with the subject invention, the chloronitrosylated hydrocarbon polymer is first blended with select additives and a blowing agent. Any desired means can be used to bring about this blending. If desired, a tworoll rubber mill or a Banbury mixer can be employed. A convenient method for forming the desired expandable blend is to mix the starting polymer with the desired additives, pass the mixture through an e'xtruder, chop the extruded material into pellets and then soak the pellets in the solvent blowing agent until the desired amount of the latter has been absorbed. The blowing agent can be mixed with a diluent, which can also contain a stabilizer or other modifier for the pretreated chlorine containing polymer, and then the polymer in finely divided form can be added and mixed into a slurry. On evaporation of the diluent an intimate mixture of the polymer and blowing agent is obtained. The foams of the present invention can also be prepared by absorbing a liquid blowing agent in a chloronitrosylated hydrocarbon polymer and then expanding the blowing agent into a gas, thereby forming cells within the polymer. For the best results, the chloronitrosylated hydrocarbon polymer is impregnated with blowing agent at an elevated temperature under sufficient pressure to maintain the blowing agent in at least a partially liquefied state, and then the polymer is directly foamed by releasing the pressure at a temperature above the boiling point of the blowing agent.

The chloronitrosylated hydrocarbon polymer particles, impregnated with blowing agent by the absorption process, can be made into foam in a number of ways. In one process, the particles are fed through an extruder in which the extrusion cylinder and/or stock screw are equipped with heating means, and as the chloronitrosylated hydrocarbon polymer is advanced through the extrusion cylinder, it is converted to a viscous melt having a temperature above the boiling point of the blowing agent absorbed therein. While the polymer is confined within the extrusion cylinder, the blowing agent cannot expand, and heating the blowing agent above its boiling point generates high pressure within the extruder. When the hot composition is forced through the extruder head into a zone of lower pressure, the blowing After placing the particles in the mold, they are heated to a temperature above the boiling point of the blowing agent absorbed therein and above the softening point of the polymer to thereby expand the particles and form a cellular product having the shape of the mold. The mold is then cooled prior to removal of the molded product.

The following examples illustrate the invention. All parts are by weight unless otherwise indicated. In the examples which follow, the percent chlorine was determined by the Mohr Chlorine Procedure and the percent nitrogen was determined by the Dumas Nitrogen Procedure. The physical properties of the cross-linked cellular polymers were determining according to Standard ASTM Procedures.

EXAMPLE I A. Preparation of Chloronitrosylated, Chlorinated Polyethylene A reaction vessel equipped with a thermometer, stirrer, condenser and heat exchange means was charged with 29,520 parts of trichlorofluoromethane and 4,000 parts of chlorinated polyethylene having a chlorine content of 27 percent, a melt flow index of 0.1 gram per minutes and a density of 1.1. Under a nitrogen atmosphere, the charge was heated to 24 C. at which temperature refluxing occurred. While maintaining the charge at this temperature, 500 parts of nitrosyl chloride was passed through the reaction vessel in the presence of a quartz l-Ianovia 500-watt lamp for a period of 10 hours. After the end of the 10-hour period, the reaction mixture was cooled to room temperature and the product isolated by filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing product indicated 28 percent chlorine and 0.1 percent nitrogen. B. Flexible Foam Prepared from the Above-described Chloronitrosylated, Chlorinated Polyethylene To 100 parts of the chloronitrosylated, chlorinated S'liiiib'eiiiiiliulh 11.43 Tensile Strength, psi Elongation, 11 I60 Graves Tear, i 12.2 Bashore Resilience 36 50% Compression Set, Set

ASTM 1565 80.0 ASTM 1564 90.6 Oxy en Index 22.3 Solu ility, boiling chlorobenzene Insoluble EXAMPLE ll This example illustrates the preparation of a flexible foam from the chloronitrosylated, chlorinated polyethylene, described in Example 1, employing an inorganic blowing'agent. To 100 parts of the polymer, 5 parts of magnesium oxide and twenty parts of a chlorinated biphenyl plasticizer having 42 percent chlorine was added 7.5 parts of sodium bicarbonate. The mixture was then sheeted on a cold rubber mill. One hundred parts of the sheeted polymer mixture was molded in a V4 inch X 6 inch X 6 inch mold at 300 F. for 1 hour and the foamed product was removed from the mold while hot. The cross-linked foam exhibited the following physical properties:

Section Density, lbs/ft 19.57 Tensile Strength, psi 206 Elongation, k 1 l0 Graves Tear, i 36.8 Bashore Resilience 20 50% Compression Set, Set

ASTM 1565 68.0 ASTM 1564 87.5 Oxygen Index 23.0 Solubility, boiling chlorobenzene Insoluble Twenty-five parts of the sheeted polymer mixture was molded in a inch X 6 inch X 6 inch mold 'at 300 F. for 1 hour and the foamed product was removed from the mold while hot. The cross-linked foam exhibited the following physical properties:

Section Density, lbs/ft" 25.0 Tensile STrength, psi 280 Elongation, Graves Tear, pi 73.3 Bashore Resilience 19 50% Compression Set, Set

ASTM 1565 60.0 ASTM 1564 90.5 Oxygen Index 23.0 Solubility, boiling chlorobenzene Insoluble EXAMPLES III-IX Following the procedure described in Example I, several foams were prepared from the chloronitrosylated, chlorinated polyethylene described in Example 1. Details of the preparations and physical properties of the resulting foams are presented in Table I. All foams were prepared in V4 inch X 6 inch X 6 inch molds at 150 C. for 1 hour. In Examples 111 and Vl-IX, 80 parts of compounded polymer were charged into the mold. 1n Examples 1V and V, 60 parts and parts, respectively, were charged into the mold.

TABLE I Examplo III IV V VI VII VIII IX Polymer, parts 100 100 100 I 100 100 100 100 Magnesium oxide, pnrts 5 5 5 5 5 5 (lilnrlnnlml biphenyl (42% 0] lorlno), part 40 20 'lrlcrvsyl phosphate, purts Dioctylphtllalutv, purts Azodicarbonnmldn, parts 10 7.5 15

p,p-Oxybis(benzcncsull'onyl llydruzide), parts.

p tam t y1 n tctrumine, parts.....IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII: 7. 5 u

TABLE I -('ontinucd Example III IV V VI VII VIII IX Physical pro erties: w v v Section ensity, lbs/1m 13, 77 21. 5 19.92 9. so 9. s9 30. 1 l8. 1 I Tensile strength, p.s 1 89 206 112 66 71 173 114 Elongation, percent 130 65 60 100 115 110 110 Graves tear, P 19. 8 44. 17. 6 l3. 6 16. 2 49. 6 44. 6 Bashore resilience 34 22 16 39 36 0 27 50% compression set, percent set' ASTM 1565 63. 2 54. 9 47. 2 80. 8 85. 7 51. 1 AS'IjM 1564 95. 1 7e. 6 9a 0 95.1 04. 2 93. 3 0 Oxygen index 2 3 23. 0 23. 0 24.1 1- 5 Solubility, boiling chlorobenzene uble Insoluble Inso uble Insoluble Insoluble Insoluble Insoluble Insol EXAMPLES X-XIII A. Preparation of Chloronitrosylated Polyethylene A reaction vessel equipped with a thermometer, stirrer, condenser and heat exchange means was charged with 2,952 parts of trichlorofluoromethane and 402 parts of polyethylene having a molecular weight of about 60,000, a melt index of 20 and a density of 0.926. Under a nitrogen atmosphere, the charge was heated to 24 C. at which temperature refluxing occurred. While maintaining the'charge at this temperature, 20 parts of nitrosyl chloride was passed through the reaction vessel in the presence of sunlight for a total period of 24 hours. After the end of the 24-hour period, the reaction mixture was cooled to room temperature and the product isolated by filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing product indicated 3.5 percent chlorine and 0.02 percent nitrogen.

- Following the procedure described in Example 1, four foams were prepared from the above-described chloronitrosylated polyethylene. Details of the preparations and physical properties of the foams are presented in Table II. In each example, 100 parts of the milled and sheeted polymer mixture was charged to a mold for 1 hour at 300 F. under 60,000 pounds of pressure.-

TABLE II Example: X XI XII XIII polymer, parts 100 100 100 100 magnesium oxide, 5 5 5 5 parts dicumylperoxide, 2 2 parts azodicarbonsmide, 7.5 parts p,p-oxybis(ben 7.5 7.5 7.5 -zenesulfonyl hydrazidc), parts physical properties section density, lbs/ft 50.1 25.7 38.1 19.4 tensile strength psi 263 354 1530 1455 elongation "28 5 63 q, graves tear, 41 59 120 221 p1 bashore re- 27 30 28 35 silience 50% compres -sion set, '5 set ASTM 1565 50.5 54.2 65.4 550 ASTM 1564 65.6 78.7 68.4 73.3 oxygen index 17.67 19.94 20.14 17.25 solubility, insoluble insoluble insoluble insoluble boiling chlorobenzene EXAMPLES XIV-XVI A. Preparation of Chloronitrosylated, Chlorinated Polyethylene A reaction vessel equipped with a thermometer, stirrer, condenser and heat exchange means was charged with 8,856 parts of trichlorofluoromethane and 2,000 parts of chlorinated polyethylene having a chlorine content of 48 percent, less than 2 percent residual crystallinity and a bulk density of 28 lbs/ft. Under a'nitrogen atmosphere, the charge was heated to 24 C. at which temperature refluxing occurred. While maintaining the charge at'this temperature, 118 parts of nitrosyl chloride was passed through the reaction vessel in the presence of a quartz I-lanovia SOO-watt lamp for a period of 64 hours. After the end of this period, the reaction mixture was'cooled to room temperature-andthe product isolated by filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing product indicated 49.9 percent chlorine and 0.05 percent nitrogen.

Following the procedure described in Example 1, three foams-were prepared from the above-described chloronitrosylated, chlorinated polyethylene. Details of the preparations and physical properties of the foams are presented in Table III. In each example, parts of the milled and sheeted polymer mixture was charged to a mold for 1 hour at 300 F. under 60,000 pounds of pressure.

TABLE III Example: XIV XV XVI Polymer, parts 100 100 100 magnesium oxide, parts 5 5 5 tricresyl phosphate, parts i 20 azodicarbonamide, parts 7.5 7.5 p,p'-oxybis( benzenesulfonyl 7.5

hydrazide), parts physical properties Section Density, lbs/ft 23.7 49.5 50.1 Tensile Strength, psi 840 181 240 Elongation, I: 295 423 435 Graves Tear, pi 164 40 59 Bashore Resilience 1'6 0 0 50% Compression Set, I: Set

ASTM 1565 53.5 101.4 99.2 ASTM 1564 86.7 115.1 96.1 Oxygen Index 35.11 35.77 36.41 Solubility, boiling insol insol insol chlorobenzene -uble -uble -uble EXAMPLES XVII AND XVIII A. Preparation of Chloronitrosylated, Chlorinated Polypropylene A reaction vessel equipped as described in Example I was charged with 1,565 parts of l,l,2-trichloro-l,2,2- trifluoro-ethane and parts of polypropylene having a melt flow rate of 12 grams per 10 minutes'and a density of 0.904. Under a nitrogen atmosphere, the charge was heated to 48 C. at which temperature refluxing occurred. While maintaining the charge at this temperature, chlorine has was introduced into the reaction vessel in the presence of a quartz I-Ianovia 500-watt lamp for a period of 2 hours. While maintaining the charge at this temperature, 15 parts of nitrosyl chloride was passed through the reaction vessel in the presence of a quartz I-Ianovia SOO-watt lamp for a period of 8 hours.

After the end of the reaction period, the reaction mixture was cooled to room temperature. The product was isolated by filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing product indicated 23.6 percent chlorine and 0.06 percent nitrogen. B. Flexible Foams Prepared from the Above-Described Chloronitrosylated, Chlorinated Polypropylene Following the procedure described in Example 1, two foams were prepared from the above-described chloronitrosylated, chlorinated polypropylene. Details of the preparations and physical properties of the foams are presented in Table IV. In each example, 50 parts of .the milled and sheeted polymer mixture was charged to a' mold for 1 hour at 300 F. under 60,000 pounds of pressure.

TABLE IV Example: XVII XVIII Polymer, pans 50 50 Magnesium Oxide, pans 2.5 2.5 Dicumyl Peroxide, parts I Azodicarbonamide, pans 4 p,p'-oxybis(benzenesulfonyl 4 hydrazide), parts Physical Properties Section Density, lbs/ft 2L2 36.4 Tensile Strength, psi 969 I405 Elongation, 6 l2 Graves Tear, pi 91 59 Bashore Resilience 27 34 50% Compression Set, Set

ASTM 1565 65.2 57.8 ASTM 1564 96.6 78.1 Oxygen Index 22.1 21.8 Solubility, Insoluble Insoluble boiling chlorobenzene EXAMPLES XIX AND XX A. Preparation of Chloronitrosylated, Chlorinated Polypropylene A reaction vessel equipped as described in Example I was charged with l ,565 parts of trichlorofluoromethane and 120 parts of polypropylene having a melt flow rate of 12 grams per minutes and a density of 0.904. Under a nitrogen atmosphere, the charge was heated to 24 C. at which temperature refluxing occurred. While maintaining the charge at this temperature, chlorine gas was introduced into the reaction vessel in the presence of a quartz Hanovia 500-watt lamp for a period of 5 hours. While maintaining the charge at this temperature, parts of nitrosyl chloride was passed through the reaction vessel in the presence of a quartz I'Ianovia 500-watt lamp for a period of 7 hours. After the end of the reaction period, the reaction mixture was cooled to room temperature. The product was isolated by filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing product indicated 33.74 percent chlorine and 0.05 percent nitrogen. B. Flexible Foams Prepared from the Above-Described Chloronitrosylated, Chlorinated Polypropylene Following the procedure described in Example I, two foams were prepared from the above-described chloronitrosylated, chlorinated polypropylene. Details of the preparations and physical properties of the foams are presented in Table V. In each example, 50 parts of the milled and sheeted polymer mixture was charged to a mold for 1 hour at 300 F. under 60,000 pounds of pressure.

EXAMPLE-XXI A. Preparation of Chloronitrosylated, Chlorinated Polyethylene A reaction vessel equipped with a thermometer, stirrer, condenser and heat exchange means was charged with 31,200 parts of l,l,2-trichloro-l,2,2- trifluorornethane and 4,000 parts of chlorinated polyethylene having a chlorine content of 36 percent, less than 2 percent residual crystallinity and a bulk density of 28v lbs/ft. Under a nitrogen atmosphere, the charge was heated to 29 C. While maintaining the charge at 29 C., 4l2 parts of nitrosyl chloride was passed through the reaction vessel in the presence of a quartz I-Ianovia 500-watt lamp for a period of 7 hours. After the end of this period, the reaction mixture was cooled to room temperature and the product isolated by. filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing product indicated 38.2 percent chlorine and 0.07 percent nitrogen. B. Flexible Foam Prepared from the Above-Described Chloronitrosylated, Chlorinated Polyethylene by Extrusion Technique A dry blend was prepared from 100 parts of the chloronitrosylated, chlorinated polyethylene described above, 5 parts of magnesium oxide, 7.5 parts of p,p'-oxybis(benzenesulfonyl hydrazide) and 20 parts of tricresylphosphate. This resulting composition was charged into a single screw, low compression, table model laboratory plastic extruder, manufactured by the Wayne Machine & Die Company, having an L/D ratio of 20:1, a screw diameter of 54 inch and screw speed of 50 to rpm. The extruder is heated electrically by resistance heaters and the hold-up time in the extruder is 3 to 5 minutes. The extrudate was a cellular material,

approximately-three times the volume of a similar solid extrudate and was insoluble in boiling chlorobenzene indicating cross-linking. The sample was self-extinguishing. v

EXAMPLE XXII A. Preparation of Chloronitrosylated, Chlorinated Polyethylene A reaction vessel equipped with a thermometer, stirrer, condenser and heat exchange means was charged with 31,200 parts of l,l,2-trichloro-l,2,2 trifluoromethane and 4,000 parts of chlorinated polyethylene having a chlorine content of 36 percent, less than 2 percent residual crystallinity and a bulk density of 28 lbs/ft. Under a nitrogen atmosphere, the charge was heated to 29 C. While maintaining the charge at 29 C., 412 parts of nitrosyl chloride was passed through the reaction vessel in the presence of a quartz l'lanovia 500-watt lamp for a period of 7 hours. After the end of this period, the reaction mixture was cooled to room temperature and the product isolated by filtration and dried under ambient conditions to constant weight. Analysis of the fine, free-flowing 'product indicated 38.2 percent chlorine and 0.07 percent nitrogen. B. Flexible Foam Prepared from the Above-Described chloronitrosylated, Chlorinated Polyethylene by Fluorocarbon Blowing Agent Process One hundred parts of the chloronitrosylated, chlorinated polyethylene described above and 295 parts of trichlorofluoro-methane were charged into a stainless steel bomb, sealed and heated for 60 minutes at 100 C. The bomb was cooled to room temperature before being opened. The swollen crumb was patted dry with absorbent paper and had increased in weight to 235 parts, indicating that 135 parts of fluorocarbon had been absorbed. Twenty-five parts of this swollen crumb was pressed between Mylar sheets at 300 F. at 10 tons ram pressure for 10 minutes to yield a cellular elastomer which was insoluble in boiling chlorobenzene. Physical properties of the foam are presented below:

Tensile Strength, psi 630 300% Modulus, psi S50 l00% Modulus, psi 190 Elongation, b 340 Graves Tear, I58 Compression t, Iv Set ASTM 1564 ll3.5

Densit lbs/ft 76.2 Solubi ity, boiling chlorobenzene Insoluble What is claimed is: l. A cross-linked cellular plastic obtained by heating at a temperature from 50 to 250 C. in the presence of hlor' c 4.

a blowing agent a chloronitrosylated polymer selected from the group consisting of polyolefins and chlorinated polyolefins, said chloronitrosylated polymer having a chlorine content of from 0.05 to 73 percent by weight and a nitrogen content of from 0.01 to 5 percent by weight. 2. .The cellular plastic of claim 1 wherein the chloronitrosylated polymer is chloronitrosylated polyethylene.

3. The cellular plastic of claim 1 wherein the chloronitrosylated polymer is chloronitrosylated,

gilii' sr claim 1 wherein the blowing agent is azodicarbonamide.

5. The cellular plastic of claim 1 wherein the blowing agent is p,p'-oxybis(benzenesulfonly hydrazide).

6. The cellular plastic of claim 1 wherein heating occurs in the presence of an acceleraton 7. The cellular plastic of claim 6 wherein the accelerator is magnesium oxide.

8. The cellular plastic claim 1 wherein heating occurs in the presence of a plasticizer.

9. The cellular plastic of claim 8' wherein the plasticizer is selected from the group consisting of chlorinated biphenyl, dioctylphthalate and tricresylphosphate.

10. A process for the preparation of a cross-linked cellular plastic comprising heating at a temperature of from 50 to 250 C. in the presence of a blowing agent a chloronitrosylated polymer selected from the group consisting of polyolefins and chlorinated polyolefins and having a chlorine content of from 0.05 to 73 percent hy weight and a nitrogen content of from 0.01 to 5 percent by weight.

11. The process of claim 10 wherein the chloronitrosylated polymer is chloronitrosylated polyethylene.

12. The process of claim 10 wherein the chloronitrosylated polymer is chloronitrosylated, chlorinated polyethylene.

13. The process of claim 10 wherein the blowing agent is azodicarbonamide.

14. The process of claim 10 wherein the blowing agent is p,p'-oxybis(benzensulfonly hydrazide).

15. The process of claim 10 wherein heating occurs in the presence of an accelerator.

16. The process of claim 10 wherein the accelerator is magnesium oxide.

17. The process of claim 10 wherein heating occurs in the presence of a plasticizer.

18. The process of claim 17 wherein the plasticizer is selected from the group consisting of chlorinated biphenyl, dioctylphthalate and tricresylphosphate.

I i i i 

2. The cellular plastic of claim 1 wherein the chloronitrosylated polymer is chloronitrosylated polyethylene.
 3. The cellular plastic of claim 1 wherein the chloronitrosylated polymer is chloronitrosylated, chlorinated polyethylene.
 4. The cellular plastic of claim 1 wherein the blowing agent is azodicarbonamide.
 5. The cellular plastic of claim 1 wherein the blowing agent is p,p''-oxybis(benzenesulfonly hydrazide).
 6. The cellular plastic of claim 1 wherein heating occurs in the presence of an accelerator.
 7. The cellular plastic of claim 6 wherein the accelerator is magnesium oxide.
 8. The cellular plastic claim 1 wherein heating occurs in the presence of a plasticizer.
 9. The cellular plastic of claim 8 wherein the plasticizer is selected from the group consisting of chlorinated biphenyl, dioctylphthalate and tricresylphosphate.
 10. A process for the preparation of a cross-linked cellular plastic comprising heating at a temperature of from 50* to 250* C. in the presence of a blowing agent a chloronitrosylated polymer selected from the group consisting of polyolefins and chlorinated polyolefins and having a chlorine content of from 0.05 to 73 percent by weight and a nitrogen content of from 0.01 to 5 percent by weight.
 11. The process of claim 10 wherein the chloronitrosylated polymer is chloronitrosylated polyethylene.
 12. The process of claim 10 wherein the chloronitrosylated polymer is chloronitrosylated, chlorinated polyethylene.
 13. The process of claim 10 wherein the blowing agent is azodicarbonamide.
 14. The process of claim 10 wherein the blowing agent is p,p''-oxybis(benzensulfonly hydrazide).
 15. The process of claim 10 wherein heating occurs in the presence of an accelerator.
 16. The process of claim 10 wherein the accelerator is magnesium oxide.
 17. The process of claim 10 wherein heating occurs in the presence of a plasticizer.
 18. The process of claim 17 wherein the plasticizer is selected from the group consisting of chlorinated biphenyl, dioctylphthalate and tricresylphosphate. 